When it comes to justice, humanity is in a state of flux. On the upside, world poverty and malnutrition have fallen since the turn of the century, and average life expectancies and literacy rates have risen. On the downside, extremes of wealth and poverty have grown wider, and civil strife, terrorism and gun violence have spiralled. Governments desperate to regain control have responded by side-lining human rights - from China's crackdown on Uighurs to military repression in Egypt and the bloody battle for Syria. But what exactly is justice? Does it mean everyone should be treated the same, even when it comes to things like taxes or welfare? And how is it enforced? Such questions have exercised the minds of thinkers since Plato and Aristotle. In this highly topical introduction, Professor Raymond Wacks breaks down the leading theories of justice to illustrate how present-day challenges affect our fundamental notions of fairness and freedom.